Many scientists rely on mice as test subjects to examine the biological symptoms of dementia, particularly mice genetically altered to develop the condition in their brains. But cats can also develop dementia spontaneously during their lives and experience the same buildup of amyloid plaques in their brains as humans with Alzheimer’s disease. A team at the University of Edinburgh recently used immunohistochemistry and confocal microscopy to examine feline brain tissue for similarities with human brains affected by dementia. Robert McGeachan, a practicing veterinarian and clinical lecturer at Edinburgh whose doctoral research focused on Alzheimer’s disease, said pets are sometimes brought to a veterinarian’s office with symptoms similar to those of human patients with Alzheimer’s and dementia. These symptoms might include confusion and disorientation, loss of vocalization, or the disruption of sleep cycles. But the pathology of the condition has remained largely unexplored in these animals. In their study, the researchers used a Leica confocal laser scanning microscope with an oil immersion objective to examine feline brain tissue — obtained from the Royal School of Veterinary Studies — for evidence of several biomarkers and, thus, confirmation of amyloid pathology. They examined image stacks from regions both with and without plaque buildup and found that amyloid protein accumulated around synapses. Their investigation identified hyperactive microglia and astrocytes — cells that typically support nervous system function but can become toxic when dysfunctional — collected in the same areas of the tissue (www.doi.org/10.1111/ejn.70180). McGeachan said the research team was reluctant to jump to conclusions because they used samples from only a small group of cats. In the future, McGeachan hopes to examine more feline subjects, for tau protein (also prevalent in Alzheimer’s cases), as well as other biomarkers, such as changes in the blood. Other optical technologies are also being used to learn more about neurodegenerative diseases such as Alzheimer’s. As Ross Keyashian from HORIBA writes on page 44, fluorescence lifetime imaging has been used to observe changes in the lifetimes of pigments such as lipofuscin, which accumulate in the neurons of people with dementia. And, in our “3 Questions” column, René Heine of Cubert discusses the use of hyperspectral imaging, aided by artificial intelligence, to identify spectral signatures that are characteristic of Alzheimer’s disease pathology in the retina. Heine notes that this technology can capture a snapshot of data to inform a convolutional neural network. This dual approach does not provide a diagnosis but can offer vital information to those who do. Perhaps best of all, retinal examination is a part of many people’s medical routines — particularly for older adults — making early diagnosis, before the onset of more serious symptoms, possible. Enjoy the issue! i